Ninety percent of acutely poisoned patients are treated within four hours of ingesting poisons by mouth. Inhibition of poison absorption from the gut is an important part of such initial treatment. Dilution, emesis, lavage, adsorbents, cathartics and enemas have been recommended for use. Dilution is known to hasten and facilitate poison absorption and to increase poison lethality when drugs or noncaustic poisons are taken. Enemas have not yet been studied thoroughly. In the present studies osmotic cathartics (mannitol plus sorbitol) and castor oil do not alone inhibit poison absorption and decrease the efficacy of activated charcoals. Lavage of the stomach recovers one-third of instilled soluble and particulate markers, but half of this recover is achieved with initial aspiration. Lavage marker recoveries are equivalent when the lavage fluid is water or isosmolar (0.15M) NaCl instilled at 0 degrees C or 45 degrees C. Highly active charcoals given with test drugs to animals decrease plasma drug concentrations by 65 to 93%. A new charcoal derived from petroleum with interpore walls of 1.1 carbon atom thickness has greater in vitro maximum adsorptive capacity and greater in vivo activity in protecting rodents from acute lethality of test drugs and in diminishing the plasma concentration of drugs in dogs. This Petrochar charcoal diminishes the plasma concentration-time integral of acetaminophen by 90% when used alone and by 99.5% when given together with a potent emetic. The acute lethality of acetaminophen in mice is decreased more with Petrochar than the next most active charcoals. New congeners of apomorphine and morphothebaine have been tested in mice, dogs and human volunteers. Tapmot, a morphothebaine congener, is 33 times more potent than apomorphine, two-thirds as lethal, induces vomiting in man after 2 mcg/kg doses intravenously, and has minimal side effects. Emesis with Tapmot effects recovery of 50% (threshold dose) to 65% (large dose) of markers placed in the stomach 55 to 5 minutes before emetic.